<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>$课堂练习$</title>
</head>
<body>
<a href="../images/1.jpg" id="ak"><img src="../images/2.jpg" alt=""></a>
<img src="" alt="" id="big">
<script src="../common.js"></script>
<script>
    my$("ak").onclick = function () {
        my$("big").src = this.href;
        return false;
    };
</script>


</body>
</html>